Apparatus for forming and vulcanizing rubber articles.



` N. W. MCLEOD. APPARATUS FOR .FORMING AND VULCANIZING RUBBER ARTICLES.

APPLICATION FILED MAY 4. IQIE.

Patented J an, 23, L91?.

I I u I N" W. MCLEOD.

APPARMUS Foa mamma AND vuLcAN'izlNG RUBBER mucus.

APPLICATON FILED MAY4. 19H5. 1,213,223. lutvnfm'l Jan. 215, lJl'.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

NELSON W. McLEOD, 0F ST. LOUIS, MISSOURI. ASSIGNOR T0 AMERICAN MOTORSTIRE COMPANY, 0F DETROIT, MICHIGAN, A CORPORATION 0F MICHIGAN.

APPARATUS FOR FORMING AND VULCANIZING RUBBER ARTICLES.

Specication of Letters Patent.

Patented Jan. 23, 1917.

Application led Hay 4, 1916. Serial No. 95,336.

To all whom it may concern:

Be it known that I, NELSON W. McLEoD, a citizen of the United States ofAmerica, a resident ofthe city of St. Louis, State of Missouri, haveinvented certain new; and useful Improvements in Apparatus for Formingand Vulcanizing Rubber Articles, of which the following is a full,clear, and exact description, reference being had to the accompanyingdrawings, forming a part of this specification.

My invention relates to a vulcanizing apparatus providing for the use ofinternal fluid pressure within a mold and against the rubber article tobe vulcanized, in order that such article may be held under uniformpressure at every point against the internal wall of the mold during theperiod of vulcanization. Vulcanizing apparatus of this kind areespecially usefulin vulcanizing hollow rubber tires such as pneumatictires or casings for automobiles.

Numerous efforts have heretofore been made to provide a vulcanizingapparatus using -fluid pressure for the distention of the rubberarticles in the uvulcanizing molds, the originators of such apparatusproposing to utilize fluid agents of various natures, for example, steamor air, 01 water which will be turned to steam when heated within therubber articles. The use of fluids of these mentioned kinds isobjectionable for different reasons, principally because they permeatethe structure to be vulcanized, or because they fail to vulcanize thestructure uniformly at all points throughout the body of rubber.Consequently, the prior apparatus have not proven entirely satisfactoryfrom a commercial standpoint.

VThe object of the present invention is to provide a vulcanizingapparatus` which permits of the use of absolute hydraulic pressureagainst the rubber articles being canized, without any lia-bility of theWater made use of for the hydraulic pressure being converted intovsteam, and with avoidance of the presence of air or steam in conjunctionwith the hydraulic pressure medium within the rubber article beingvulcanized. lVater alone is the ideal substance for use as a pressuremedium in an appa- `ratus of this kind and it is a well known fact thatthe presence of steam or air in conjunctlon with water as medlum toafford internal pressure within rubber artlcles vulto be vulcanized isobjectionable ow to permeation thereby into the rubber articles and tothe inability of transfer heat with relative uniformity through soli`bodies and gaseousbodies.

Difficulty has been experienced in discovering a way of maintaining astrictl hydraulic pressure withinA the rubber articles to be vulcanized,so that permeation would be avoided and the conductivity of the internalfluid pressure medium would be kc011- stantly uniform at all points.

My present invention is preferably carried out in a construction wherebyI eliminate air from the interior of the rubber .article to bevulcanized lill the article with water and valordl no opportunity forthe generation of steam within the Yrubber articles as will hereinafterappear. To aecomplish these resultsthe water confined vin the mold ispreferably held under such a. high degree of pressure that it will notboil when subjected to the vulcanizing tem` rature, which for example mabe 270. bwever, the water will expan as the temperature rlses and thepressure due to the expansion is very eat. I compensate for thisexpansion an prevent injury to the mold and rubber article, preferablyby the use of a device which allows the Water to expand withoutmaterially changin the pressure, at the same time maintaining the rubberarticle entirely full of water during the vulcanizing operation.

Figure I is a vertical section through my vulcanizing apparatus. Fig. IIis an enlarged fragmentary section showing the expansion device. Fig.III is an enlarged cross section through one of the molds and the airvent device'` mounted therein. Fig. IV is an enlarged cross sectionthrough one of the molds, showing an unvulcanized tire therein as itappears prior to the introduction of hydraulic pressure into the tire.Fig. V is a view partly in section, illustrating a modification.

In the drawings, I have illustrated m apparatus of )referredconstruction, Wit the article to -e treated shown as rubber tires,designated A, .the tires having two edges at their inner circles andbein built up of fabric and rubber compound, 1n any Vsuitable manner.The tires A may be artire. 'l`he abutment ring; by its position betweenthe edges of the tire. permits of the tire edges being tightly clampedbetween said abutment ring and vthe shell sections of the mold toproduce fluid tight joints, in order that water introduced into the tireoccupying.r the mold cavity, may be retained therein for the treatmentof the tire.

1 designates .a vulcanizer pot,'through which steam is circulated. thepot, with this object in view, having connected to it pipes 2 and il,one ot' which serves to admit live steam to the pot and the other ofwhich allows the steam to escape from the pot. The vulcanizer pothas aclosure 3,`whicl1 may be. held in closed position by any suitable means,access to the pot being permitted by moving, either the body ot' the potor the closure relative to the other part of the pot. The vulcanizer potis arranged to receive an abutment spider 1t beneath which the molds Bare confined as willbe presently pointed out. rThis abutment spiderpreferably extends across the vulcanizer pot` and portions of it arepositioned beneath lugs 1 extending inwardly from the wall otl thevulcanizer pot at its` upper end.

5 designates a mold moving means in the form ot' a hydraulic ramprovided with a head or table l, the latter being situated within thevulcanizer pot and being movable therein. Theram head (i serves as asupport for the molds Bpand upon the movement oi the ram and its headtoward the opposing abutment. spider t inserted after the molds ha vebeen put in place, the pressure exerted upon the sectional molds Bcauses the tires therein to be clamped within the lnolds between themold sections and the abutment ring to such degreeV as to render thejoints of the mold iiiiid tight.

Steam admitted intothe vulcanizer pot is, therefore, excluded from thevmolds. The h vdraulic ram 5 is operable in a cylinder 7, into whichwater or otherV iluid i5 introduced.

I next come to a description ot' the means by which Huid may beconducted into the molds B, for the purpose ofplirst fully cxpanding andcompressing raw tires in .said molds and, thcreai'tcr` vulcanizing theiuterior portions ol the tires. while the exterior portions ol the tiresare being vulcanized from beat transmittal through the mold shells. ltwill. however` facilitate, the description to lirst describe theautomatic valve devices C, by which communication is face of the. tireA, the pipe 9 having in its wall, near its upper end, apertures 10 whichprovide for the admission of air from the interior of the tire to theupper end of the pipe.Y At the outer end ot the tube 8 is a valve casing11, containing a valve chamber 13 in which is a valve seat 12 and an air'relief valve movable to and from said seat.

laeh ot' the abutment rings ot' the molds B contains a duct Il throughwhich water may be introduced into the tire A within the mold.

l-t designates a water conducting pipe provided with as many connections14 as there are molds. said connections being of such construction as topermit ot' the ready application ot' the connections to the abutlnentrings of the molds at the ducts 1). 'ater is delivered to the waterconducting pipe 11 from a hose or other pipe (not shown) which may bedetachably connected to a coupling extension 15 of the water conductingpipe in which is a shut off valve 16.

111 the practical use of my tire forming and vulcanizing apparatus forthe treatment of tires composed of rubber compound and fabric, I proceedas follows: The tires having been builtI up in any suitable manner areplaced in the molds B while the rubber compound is in the raw or uncuredstate, the abutment rings ot' the molds being positioned between theedges ot' the tires so as to produce tluid tight joints at such edges.lVhen the abutment rings (1 are put in place they contain the automaticair relief devices C- having the check valvesl which are normally open.

The number of tilled molds it is desired to use in the apparatus areplaced one upon another with the lowermost mold resting upon the ramhead 6. The abutment spider l is then inserted into the vulcanizer potabove the molds and in caigagement with the lugs l, thereby locking psaid abutment spider in such manner as to cause. it to conlstitute astop above the molds. The ram 5 is then elevated and the. molds becomeclamped between the ram head and the abutment spider -L '.l`he waterconducting pipe 1l is then attached to the abutment rings and anexpansion chamber Xbeing attached to said water conducting pipe theapparatus is in condition for delivery of hydraulic pressure into thetircswithin the molds.

A waterl delivery pipe (not shown) is attached to the extension of thewater conducting pipe 14 and the shut-off valve 16 being open Water isforced into the tires within the molds. As the Water enters the tiresthe air therein escapes through the automaticvalve devices C each of thevalves being open a slight distance to allow the air to escape freelywithout closing the valve. After a tire has been completel filled withwater, the waterwill begin to ow through one of the automatic valvedevices and this liquid body striking the valve will force the latter toits seat, thus closing the automatic valve device. The vulcanizer pot ispreferably open during the o eration of filling the tires with water,the c osure 3 being absent from the body of the pot. Vhen the raw tiresare first placed 'in the molds they do not necessarily fill the moldcavities, such-. cavities being preferably larger than the raw tires asillustrated in Fig. IV. The pressure under which the water is introducedinto the tires is preferably one of a. degree sufficiently high toexpand the tires to the walls of the mold cavities, although a pressureslightly less than this may be sufficient for the reason that thehydraulicpressure in the tires will be increased when the water isheated by the heating of the vulcanizer pot in the manner to behereinafter explained. When water is introduced into the tires of themolds B a kcertain quantity of the water enters the expansion chamber X,but inasmuch as this expansion chamber is a closed receptacle the watertherein cannot escape and is yheld under pressure.

The tires having been filled with water to subject theln to a desireddegree of hydraulic pressure the shut-ofi'l valve 16 is then closed andthe water delivery pipe is` disconnected from the conducting pipeextension 15. The closure 3 is then' secured to the body of thevulcanizer pot and the apparatus is in condition for service in thevulcanization of the tires. Heat is applied to the vulcanizer pot toperform the vulcanization by creating a circulation of steam throughsaid pot, the steam entering the pot through the steamn inlet pipe 2 andescaping therefrom through the outlet pipe 2". The steam in itscirculation in the pot heats the molds B and the tires therein whilesaid tires remain subjected' to constant uniform hydraulic pressure. Asthe water in the tires becomes heated it will naturally expand andbecome greater in Volume.

From the foregoing it will be understood that the tires have been filledwith Water which for various reasons is an excellent medium for thetransmission of heat during the vulcanizing operation. The cold Waterintroduced into the tires under preure, will close the pores of thetires instead of per meating the rubber and fabric, and after the waterhas been heated to the desired degree its temperature will besubstantially uniform y throughout. Moreover, the uniformity of l thetemperature of the water will not be maf terially affected by externalconditions, such for example as an open window at one side of thevulcanizer pot, and when heatedthe,y

water will not permeate the structure lto be vulcanized. There is,however, another con# dition that must be carefully observed to obtainthe benefit of the foregoing advan-y tages. The tires have been filledwith. Water,

and they are to remain full of Water wheny subjected to the vulcanizingtemperature, for

armixturel-of air and water, or steamand water, would not vulcanlze thetlres unlformly throughout, the conditions existing" at the hot waterbeing. different from the conditions produced by hot air or steam. Forthese reasons I preferably prevent the water from turning to steam at a.tempera ture of, for example, 27 0o F. and also avoid the extremely highdegree of pressure which would be caused b v the great expansive forceof water when it is confined in a closed reillustrate this feature ofthe invention I have shown a cylinder 20, closed at oneend by aI head 21and connected to the water pipe 14 through the medium of a tube 22 andsuitable coupling devices. A piston 23, mounted in this cylinder, isnormally forced against an abutment 24 by means of a spring 25, thelatter being interposed between the piston and a spring seat 26. Theforce of the spring may be regulated by an adjusting screw 27.

Some of the water introduced intothe sys` tem enters the cylinder 20,and in response to the initial pressure of the water, for example 150pounds, the piston travels a slight distance away from the cylinder head21. If any leakage should occur in the system,

the piston will be forced toward the head 2l to avoid a materialreduction in the pressure of the water. Then the water expands inresponse to the vulcanizing temperature, some of' the water is forcedinto the cylinder 20 without injuring the'tires or molds by the force ofthe expansion and Without reducing the volume of the liquid bodies inthe tires, the piston 23 being. adapted to yield when the volume ofWater in the system is increased by expansion.

Fig. V illustrates a modification comprising an expansion chamber 20having a `\"1eldable wall :23' in the form of a spring presseddiaphragm'. A water conducting pipe 22.leading to the expansion chamber20', is adapted to communicate with interior of the ti'resto bevulcanized. Some of the water introduced into the s vstem will enter theexpansion chamber 20 and when the water expands the diaph agm Q3' willyield to permit the excess water to enter the expansion chamber.

1. In an appara-tus for vulcanizing rubber articles, a mold. means forintroducing water into said mold, means for heating the water in saidmold. and means associated with said mold permitting the expansion ofthe water in the mold without permitting generation ot' steam in themold.

In an apparatus for vulcanizi'ng rubber articles` a mold, means forintroducing water into said mold, means for heating the water in saidmold. and means aside from said mold into which the water heated thereinmay expand without permitting generation of steam in the mold.

2. In an apparatus for vnlcanizing rubber articles. a mold,means forintroducing water into said mold, means for heating the water in saidmold and a closed expansion chamber having communication with theinterior ot' said mold,

Je. In an apparatus for vulcanizing rubber articles. a mold, means forintroducing water into said mold. means for heating the water in saidmold, and an expansion chamber below the plane of said mold havingcommunication with the interior of the mold.

In an apparatus for vulcanizing rubber articles. a sectional mold havingan abutment member situated between its shell sections, means forintroducing water into said mold through said abutment member, means forheating the water in said mold, and means having communication with theinterior of said mold through said abutment member into which the waterheated in said mold may expand without permitting the generation ofsteam in the mold.

G. In an apparatus for vulcanizing rubber articles, a plurality ofmolds, means or delivering water into said molds, means for heating thewater in said molds, and an expansion chamber having communication withall of said molds in common into which a portion of the water in eachmold may pass when heated without permitting the generation of steam inany of the molds.

7. In an apparatus for vulcanizing rubber articles. a mold, means forintroducing water into said mold, means for heating the water in saidmold, and a yieldable expansion dev-'ice associated with said mold andadapted to move in response to thev expansion of the water.

8. In a vulcanizing apparatus, a mold for the article to be vulcanized,means for introducing water into the article confined in the mold. meansfor heatlng the water 1n said article, and a vieldable expansion device,associated with said mold and adapted to move in response to theexpansion of the water, said yield-able expansion device permit-ting theexpansion of water in the article without pern'iitting generation ofsteam in Said article.

5l. In an apliaratus for vulcanizing rubber articles, a mold, means forintroducing water into said mold, means for heating the water in saidmold, and an expansion device having a vieldable abutment adapted to bcengaged b v the water to provide for the expansion of the water in themold.,

10. In an apparatus for vulcanizing rubber articles, a mold. means forintroducingr water into said mold. means for heating the water in saidmold, and an expansion chamber communicating with said mold, saidexpansion chamber being provided with a vieldable abutment. adapted tomove in response to the expansion ot' the water.

11. In an apparatus-for vulcanizing rub' lier articles. a mold. meansfor introducing water into said mold, means for heating the i water insaid mold. an expansion chamber associated with said mold, saidexpansion chamber being provided with a movable abutment wall. and aspring tending to prevent said abutment wall from moving in response tothe pressure of the water, said abutment wall and spring being yieldableto allow water to escape from the mold in response to theI expansion ot'the water in said mold.

12. In an apparatus for vulcanizing hollow rubber tires, a tire mold,means for introducing water into the tire confined in the mold. aventing device associated with said parts to allow the hollow tire to befilled with water, means for heating the water in the tire. and avieldable expansion device permitting the expansion of the water in thetire. y

13. In an apparatus for vulcanizing hollow rubber tires, a tire mold,`a. conductor through which water may be introduced into the tire coninedin said mold, a venting device associated with said parts to allow thetire to be filled with water, means for closing the wat-er receivingelements to maintain the tire full of water during the vulcanizingoperation, means for heating said water', and a yieldable expansiondevice permitting the expansion of the water in the tire.

14. In an apparatus for vulcanizing hollow rubber tires having separableedges, a sectional tire receiving mold, an abutment member adapted tolie between the separable edges of the tire to prevent the escape offluid at said edges, means for introducing water through said abutmentmember and into the hollow tire, a venting device associated with saidparts to allow the hollow tire to be lilled with Water, means forclosing the water receiving elements so that the tire will be full ofWater during vulcanizing operation, means for heating said Water, and ayieldable expansion device permitting the expansion of the Water in thetire.

15. In an .apparatus for vulcanizing rubber articles, a plurality ofmolds, means for conducting water into said molds, means for heating thewater in said molds, and a yieldable expansion device communicating withall of said molds, said expansion device being adapted to yield tocompensate for the expansion of the Water in said molds.

16. In an apparatus for vulcanizing rubber articles, a mold, means forintroducing water into said mold, and a compensating device associatedwith saidmold to compensate for leakage of water from the mold.

17. In an apparatus for vulcanizingrubber articles,a mold for the recetion of the article to be vulcanized, means or introducing water intothe article confined inthe mold, means for heating the Water in the:r11-ticle, and a compensating device arranged tc compensate for leakageof water from the article, said compensating device being adapted torelieve the pressure due to the expansion of the Water in the article.

NELSON W. MCLEOD.

copies nf this patent may be obtained for ve cents each, by addressingthe Commissioner o! Patenti. Washington, D. C.

